It seems to me that you're looking at "twin tips" (or "twips," as I like to call 'em) that aren't really hardcore twin tips.
I had a pair of the Karmas and they weren't a true twin tip in the way that some of the Armada, 4frnt, Ninth Ward, Faction, Liberty, and other twin dedicated company skis are.
Isn't The Bridge lumped in with Volks Freeride skis and I believe more or less replaces the Karma? If that's the case I dunno if I would call it a true twin as much as a hybrid aimed at non-park riding folks intrigued by the design.
I owned a pair of Armada AR5's, which are pretty much a true, center mounted twin that only had one mounting point (some of the more freeride oriented twins will offer Park/Pipe and Freeride mounting points that vary depending on what you intend to use the ski for). After a few days on the ski I ended up not liking it. It was a little soft and I'd mounted it back from the factory recommended line and it drove me into the back seat something fierce.
I think, based on my limited experience, I would have to second Lars credo: if you don't ride switch (and you're not hitting the park or doing freestyle acrobatics in the BC) then you really don't need to concern yourself with twips.
You will notice that all of the BIG ski companies jumped on the twin tip bandwagon after they became popular with some of the smaller companies (Armada, Line, 4Frnt). I sort of liken it to the new, busy topsheet designs (the big ski companies saw something that kids were into and realized the marketing/sales potential and went with it full bore).
That said, I have a pair of Lib Tech's in my quiver (not mounted yet) that would qualify as a twin on the surface, but the mounting point is far enough back that I don't consider them to be true twins (I always view a true twin as being more or less center mounted).
Then again, what do I really know?
SJ would be better suited to answer this question than me, but wasn't the "all mountain" ski just a marketing term created to sell more skis?
Most of us here know that there's not really such a beast as an all mountain ski, especially if you're skiing the whole mountain, rocks, slop, chop, taters, pow, slush, crud, cement, ice, cordouroy, corn, and all.